Similarity Builder

A runner game about similar figures. You run across a canyon, and at every gap a puzzle shows two similar shapes of different sizes: find the scale factor between them (level 1), or use the scale factor to find a missing side length by multiplying or dividing (levels 2 to 4, where the shapes get turned, flipped, and eventually only label one side out of each group of equal sides). Whatever number you answer is what the bridge gets built with - too small and it buckles, too large and it snaps, and either way you fall and lose a heart. Between puzzles, dodge obstacles that are the real-world reasons a bridge does not get built - protesters, endangered animals, lawyers who need permits, red tape, unstable soil, flooded land, holes, loose pipes, and electrical lines. Each level has its own obstacles, and every one costs a heart if it touches you. Jump the ones on the ground and run under the ones overhead (except a bird, drone or helicopter flying low, near the ground: jump that one), watch for boulders and barrels that roll toward you, and land on floating platforms. Some rows of obstacles come in a steady rhythm, including construction pile drivers that lift and drop: run under one that is up, jump one that is down. A quick correct answer builds a gold-trimmed bridge with fireworks. As you run farther through a level, the sky turns from day to sunset to dusk. Every correct answer earns a coin to spend in the Shop on a bridge-building crew member such as a politician, architect, engineer, electrician, or safety inspector, each in four different looks. Controls: Space, Enter, or the up arrow (or a tap) jumps, and pressing again in the air double jumps. Type whole-number answers and press Enter or the Build button. The Menu button or the Escape key pauses. From the title screen, Play opens the Menu screen, where you can start a Bridge Run, open Practice (no obstacles or hearts, with a choice of question types), or open the Shop.